CRS317/CRS326 SFP+ links drop to 1G when auto-negotiation is disabled, even with speed=10Gbps

With auto-negotiation on, CRS317 and CRS326 SFP+ interfaces ran at 10G; with auto-negotiation=no, speed=10Gbps and full-duplex=yes the log still reported link up (speed 1G, full duplex) regardless of the advertise settings. On a CCR1009 the same configuration produced no-link instead, showing that the CCR really tries 10G without negotiation while the CRS models do not.

• Hardware: MikroTik CRS317-1G-16S+, MikroTik CRS326-24G-2S+, MikroTik CCR1009
• Transceivers: 10G SFP+
• Form factor: SFP+

Symptoms / messages:

link up (speed 1G, full duplex) with auto-negotiation disabled
no-link on CCR1009 with autoneg off